S2.UI.Accordion does not hide content on initialization

[Korkonius]

Upon creating a new S2.UI.Accordion all content remains visible until a header that triggers animation is clicked.

Attached patch changes this behavior by explicitly hiding all content not specified by the (new) defaultIndex option.

I am unsure if this was an issue in the Alpha releases but with Beta 1 i have had the problem on 2 different pages using the jQuery Themeroller as several tutorials suggest should work out of the box.

Due to this being my first experience with GIT the changes are spread over 3 commits to minimize the footprint of my patch in the existing S2 code.

Best Regards, Eirik Ottesen